Lighting is often provided in facilities, such as factories and warehouses, in a manner that minimizes energy output and minimizes the number of light fixtures needed to provide the desired level of illumination. As a result, facilities are often designed to include a minimum number of light fixtures that spread the light or provide a wide throw of the light to create an even distribution of light. Light fixtures that are commonly used in industrial settings are available from, for example, Day-Brite Lighting.
Several light fixtures are designed to hang from a ceiling and provide both down lighting and up lighting. In the context of ceiling mounted fixtures, down lighting is referred to as direct lighting, and up lighting is referred to as indirect lighting. Patents that describe exemplary lighting fixtures include U.S. Pat. No. 4,472,767 to Wenman; U.S. Pat. No. 5,014,175 to Osteen et al.; U.S. Pat. No. 3,662,165 to Osteen et al.; and U.S. Pat. No. 1,946,465 to Arras.
In general, a well-lit environment can be considered one where there is sufficient light on a work surface to provide contrast and there is nothing significantly brighter or darker than the work surface in a person's field of view. The existence of glare can cause a decrease in worker productivity by obscuring detail and generally decreasing visibility. By decreasing visibility, eyes become tired, tasks requiring vision become more difficult to complete, and defects become less apparent.